This invention relates to a manually operable stop fixing device which secures a stop, such as top end and bottom end stops, to the tapes of a slide fastener. More specifically, the invention relates to an improved stop fixing device in which the operation for securing a stop to the tapes of a slide fastener is very reliable.
Upon attaching to clothes, a complete slide fastener is usually sewn as a whole onto the clothes. However, somtimes it is desired to employ a process including the steps of cutting a piece of a desired length from a continuous long fastener chain, sewing the piece to clothes and then mounting on the piece a top end stop and/or a bottom end stop and a slider to complete a slide fastener. For use in such process, a manually operable stop fixing device for slide fasteners has been well known. Such device operates in the same manner as that of a conventional device for stapling paper sheets, in which by squeezing upper and lower levers a driver descends to press down a stop, causing a die portion to bend the legs of the stop.
In the stop fixing device of this kind, a stop band consisting of a plurality of stops stuck together is loaded in an elongated guide member. By driving the leading end of the stop band, the stops are successively driven to penetrate tapes of fastener stringers and are secured thereto.
One of the stop fixing devices of this kind is disclosed in German Utility Model No. 1902794.
The stop fixing device of this kind is compact and easy to carry. Therefore, it has been advantageously used in securing stops such as bottom end stops of slide fasteners.
However, there are still some problems in connection with the stop fixing devices of this kind. Firstly, there will be no trouble if an operator presses the driver through its full stroke to completely push down the stop. However, if a user presses the driver only midway of the full stroke and then releases the levers, the stop sticks in a guide channel without being completely pushed down. If the user squeezes the levers again to press the driver for pushing down the next stop, the ends of the legs of the next stop enter the clearance between the shoulders of the former stop and the guide channel walls, thereby causing a jam. This clearance exists because the width of the guide channel is made larger than the distance between the shoulders of the stop to compensate for varitation in the shape of the stops and assembling tolerance of the stop fixing device. As a result, it is impossible to push out the succeeding stops without partially disassembling the device to remove the stuck stops therefrom.
Furthermore, since the width of the guide channel is greater than the distance between the shoulders of the stop, it is seldom that the legs of the stop are positioned normal to the plane of the tapes. Therefore, the tapes are not accurately punctured and securement of the stop is not reliable.
Secondly, upon forming having stop blank into a bottom-side-opened rectangle, the distance between the outer surfaces of the two legs of the stop varies from piece to piece. Furthermore, most stops are formed into a trapezoid in which the legs thereof diverge. Therefore, an elongated guide member, in which a stop band consisting of a plurality of stops stuck together is received, must be so formed that a certain clearance is provided between the stop band and the guide walls of the guide member for compensating for variation in shape of the stops. A plunger or follower, which is provided for sliding movement along the guide walls of the elongated guide member to forwardly urge the stop band, is also formed into a bottom-side-opened rectangle, the plate composing the follower being thicker than that of the stop. Therefore, the stop band is received in the elongated guide member with certain clearances from the opposite side walls and the upper wall.
The stop at the leading end of the stop band forwardly urged in the guide member is received in a driver guide channel, with the bottom end of the stop unsupported. Therefore, if this stop is driven, a moment is applied to the stop band about the forward edge of the guide member. Because of the existence of the abovementioned clearance, the band rotates, thereby angularly moving the leading stop from its vertical position. This causes the stop to bear against the inner wall of the driver guide channel or the lower portion of the end of the guide member. This makes the driver relatively hard to operate and also makes fixing of the stop unreliable.
Thirdly, size of user's hands of a stop fixing device varies from person to person. Therefore, unless the width of the grip defined by two levers is optimum to a user, there is possibility of misoperation.